Because of limited indoor parking lots, many cars have to park outdoors or on the streetsides on a hot summer day. In such occasions, there arises a speedily climbing temperature in the interior of the car, sometimes up to 50.degree. or over minutes or hours later, though sunbeams-shielding papers are already attached to the car windows. To enter and drive the next time, the driver may have to open wide the car doors, turn on the air conditioning unit and wait for quite a long time before the temperature therein is reduced to a bearable degree. However, even on the next driving trip, the driver may be bearing with the still quite heated seat and be steamed sweaty as a result. Some people apply an air extracting method in an attempt to equalize the car interior temperature with the exterior but with little effect shown. Now in recent years, there has been the use of a coolant sprayer with which to lower down temperature speedily. But since the user has to bend his, or her, body to enter the car and handhold it therein to spray, he, or she, may have already been quite sweaty before starting the next drive. To users, the coolant sprayer indeed has room for improvement.